What is the best "standard ISO" for the 5D MkII?

Panopeeper wrote in post #7705523
The following graphs show the reason:

the loss of dynamic range from ISO 100 to 200 is tiny; from ISO 200 to 400 it is only about 1/4 stop

This means, that the exposure can be quartered in exchange for 1/3 stop DR (i.e. going with 400 instead of 100); this is a good deal in many cases.

On the other hand, going from 400 to 800 costs almost 1/2 stop, that needs to be considered.

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Interesting graph. Any plots of ISO 125, 160, 250, 320, etc? Could be a surprise. I wouldn't expect a huge difference, but it might be interesting to see how the 1/3 stop settings perform relative to the "standard" ISO ratings.

clupica wrote in post #7700337
Well, you know how it is. there may be a discussion of this around here soemwhere but I can't find it.

What is the best all-around default ISO for the Canon 5D Mark II. When going throught the manual I see that some of the Canon defaults are set to ISO 400. I mean, this seems a bit high to me. Should I use ISO 400 as the default or should use ISO 100 or 200 instead. I shoot a lot of outdoor / nature / full daylight and don't usually have a need to more than 200. If I do, I can usually use a longer shutter speed and a tripod (ie: macros).

Any recommendations / thoughts on this ?

Charlie

If we look at what the OP has stated here the answer would probably be ISO 100. Crap, he's not shooting for NASCAR! The responses should be according to what he shoots.

If you shoot still life in your den 50 or 100 would be your best all around setting. If you're always shooting aircraft in flight maybe 6400 is your number. There is no best all around ISO for everybody especially with all the different lenses available.

Have to go, need to adjust my sleep number bed. Is there a best all around setting for that?

seaside wrote in post #7706993
Have to go, need to adjust my sleep number bed. Is there a best all around setting for that?

6. Everyone knows that.

Panopeeper wrote in post #7705876
If it is too complicated for you, then simply ignore it.


Honestly, do you understand this?


Too high in what respect? Are you scared by high numbers?

Nice bedside manner there, doc. I understand your graph fine. My point was that you're analyzing the reasoning behind ISO 400 too deeply. Good graph, and informative in its own way, but not necessarily the reason behind having 400 be the default ISO for certain settings. But feel free to continue belittling others if it makes you feel good.

Again, for others who are in it for the discussion and not the name-calling, my point is that 400 is simply a happy medium for an "auto" mode. It's high enough to avoid camera shake in a lot of situations, and also low enough to both minimize noise and avoid an exposure where shutter speed is max-ed out while aperture is stopped way down. It will never cover every shooting situation, but we're talking about a good all-around ISO, not one that will be applicable to all shooting situations. That's why we have adjustable ISO after all.

ed rader wrote in post #7705828
that really depends. if you are talking about landscapes with a CPL i agree. otherwise it just depends. if i'm shooting @ f2.8 with a 50mm lens iso 400 is way overkill.

ed rader

Of course. Canon's default ISO isn't for everybody. For instance, I'm very rarely under ISO 800 myself, just because I almost never have the chance to shoot in good light.

Tom W wrote in post #7706909
Interesting graph. Any plots of ISO 125, 160, 250, 320, etc?

This is not the question of plots but of taking and recording the measurements. It is quite time consuming; I got shots of a color checker sheet, and I pick the measurements on 26 patches, separate for the three raw channels.

I did this for ISO 250, only as a demo. There is no point in it, because the camera does not have ISO gains for the 1/3 stop ISOs. 160, 320, 640 and 1250 are identical to 200, 400, 800 and 1600, respectively; the pixel values are simply multiplied by 0.8 (roughly 1/1.26, corresponding to 1/3 EV). Look at the fine histogram of an ISO 640 shot underneath: every fourth pixel value shows much higher "presence" than the others (the y axis is logarythmic, the small spike represents twice as many pixels with that value).

The full stop + 1/3 ISO steps are much worse: they are not from the next lower ISO step, as with the 40D, but from the higher steps. Correspondingly, the noise of ISO 250 is as much as with ISO 400.

See the other head about related issues: EOS 5D Mark II Noise Reduction in RAW

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Yohan Pamudji wrote in post #7707320
Nice bedside manner there, doc. I understand your graph fine. My point was that you're analyzing the reasoning behind ISO 400 too deeply. Good graph, and informative in its own way, but not necessarily the reason behind having 400 be the default ISO for certain settings. But feel free to continue belittling others if it makes you feel good.

Again, for others who are in it for the discussion and not the name-calling, my point is that 400 is simply a happy medium for an "auto" mode. It's high enough to avoid camera shake in a lot of situations, and also low enough to both minimize noise and avoid an exposure where shutter speed is max-ed out while aperture is stopped way down. It will never cover every shooting situation, but we're talking about a good all-around ISO, not one that will be applicable to all shooting situations. That's why we have adjustable ISO after all.

Well wrote sir.

wilky

Yohan Pamudji wrote in post #7707320
...
my point is that 400 is simply a happy medium for an "auto" mode. It's high enough to avoid camera shake in a lot of situations, and also low enough to both minimize noise and avoid an exposure where shutter speed is max-ed out while aperture is stopped way down. It will never cover every shooting situation, but we're talking about a good all-around ISO, not one that will be applicable to all shooting situations. That's why we have adjustable ISO after all.

Well spoken and thanks and Panopeeper I like the charts and find them very informing. With these two responses I can now confortably use ISO 200 most of the time and switch to 100 or 400 as the case demands. It seems evident that using the 1/3 stop intermmediates has no partical value (in most cases) since using full-stop ISOs can easily be coupled with a change in shutter speed and/or a change in aperature.

I'm glad I could spark such a lively discussion.
Charlie

You change ISO when you get too low/high shutter speed with selected aperture. Aperture is the the decision that matters most, it "defines" the photo. To make sure you have required shutter speed for the shot you change ISO as much as needed. Forget fear for big numbers and noise charts, make use of them all. Don't let numbers drive your decisions.

Panopeeper wrote in post #7707433
This is not the question of plots but of taking and recording the measurements. It is quite time consuming; I got shots of a color checker sheet, and I pick the measurements on 26 patches, separate for the three raw channels.

Your efforts are certainly appreciated.

The reason I mentioned it was that I'd seen (on another forum) some visible evidence that the noise performance of the 5D2 appeared to be better at 160, 320, 640, etc than it was on the corresponding 200, 400, 800, etc settings (essentially cleaner at 1/3 stop slower). I realize that's not exactly what you were measuring, but I was interested in some measured data that would go along with my observation. I haven't taken the time to visually test my own 5D2 for this yet. I'm still somewhat enjoying the clean performance in the 800-3200 range.

I'll look it over as well - thanks. I'll also study the chart you pasted in the thread. Lots of information there.

clupica wrote in post #7708543
Well spoken and thanks and Panopeeper I like the charts and find them very informing. With these two responses I can now confortably use ISO 200 most of the time and switch to 100 or 400 as the case demands. It seems evident that using the 1/3 stop intermmediates has no partical value (in most cases) since using full-stop ISOs can easily be coupled with a change in shutter speed and/or a change in aperature.

I'm glad I could spark such a lively discussion.
Charlie

If it means anything, I used to "park" my classic 5D at ISO 400 and used it more often than not. It was plenty clean at that setting, and it appears that the 5D2 is even cleaner. I would adjust the ISO according to the situation. I never avoided using the 1/3 stops, but rarely used them since I didn't need to adjust my other exposure settings by that small of an amount very often.

I enjoy these discussions when the charts and graphs start showing up - it brings out the inner engineer from within.

Choosing ISO isn't simply depend on "can I tell a difference?" In a well- or over-exposed shot, you probably won't see any difference until ISO3200. However, just because it looks good to you doesn't mean you didn't lose dynamic range, and if you want to boost the exposure or bring up the shadows, the ISO setting can make a big difference.

I try to use ISO 100, but I have no qualms going to the maximum if I have to.

On 1/3 stop increments, don't bother using them if you shoot RAW. I heard they're "real" ISOs on 1D bodies, but I haven't confirmed it.

Noise with fractional ISO steps

I added ISO 250 and 320 to the graphs. ISO 320 is identical to ISO 400 - this is, how it is expected.

ISO 250 is strange. It is derived from ISO 200 by multiplication (stretching) as make-up for the lower exposure than with ISO 200; see the fine histogram

However, this is not so with the 5D2. There is no visible numerical adjustment, which indicates that it is derived from ISO 400 by dividing the pixel values by 2 (this would not leave any visible traces in the image). The noise with 250 is the same as with 400; this supports the above finding. However, some other details are not supporting it; I would have to get further shots and analyze them - but who cares for ISO 125, 250, 500, 1000 when shooting raw?

Anyway, the following graphs show, that ISO 250, 320 and 400 are vistually identical.

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Gabor, youre graphs are interesting. I'm more into practical photography so I need to comment some

When shooting real images you change ISO in order to get exposure right, or more (or less) shutter speed for chosen aperture/lens combination. Shooting a scene with ISO 3200 f/1.2 85mm is not same as shooting it with ISO 800 and pushing RAW converter +2 stops. By underexposing the original you will loose shadow detail for good and by boosting exposure you will cut highlights. With proper exposure you get an original which has most "good" data to work with. Point of photography is to get a good file with properly exposed subject.

That is why I'm not a fan of advice which tells intermediate ISO's are not useful or that ISO 3200 is same as 1600, i.e. "same data pushed internally". When it is stored to a file it's not the same data any more.

Pekka wrote in post #7710775
When it is stored to a file it's not the same data any more.

Pekka,

I have several comments re your statements, but first I would like to understand what you mean by "not the same data any more".